1. Field of the Invention
The present invention relates to a full-color plasma display panel, and more particularly, to a plasma display panel using different discharge gases to emit variant colors of light.
2. Description of the Prior Art
A full-color plasma display panel (PDP) is a common type of flat display that uses discharge gases to emit multi-color lights. The luminescent performance of the PDP is made by the millions of tiny discharge cells for emitting fluorescent lights of various colors. The prior PDP includes phosphor materials coated in these tiny discharge cells. The dimensions of these cells can be in the order of a few hundred microns. Each of the cells is filled with a discharge gas of a mixture of neon (Ne) and xenon (Xe), or a mixture of helium (He) and xenon (Xe). When the plasma is excited, the discharge gas emits ultraviolet light and the ultraviolet light in turn irradiates the phosphor materials to result in the emission of red, green or blue light.
Please refer to FIG. 1. FIG. 1 is a perspective view of a full-color PDP 10 according to the prior art. The prior PDP 10 includes a first substrate 12, a second substrate 14 parallel to the first substrate 12, and a discharge gas (not shown) that fills the space between the first substrate 12 and the second substrate 14. The prior PDP 10 further includes a plurality of first electrodes 18, a plurality of second electrodes 20, and a plurality of third electrodes 22. The first electrodes 18 and the second electrodes 20 are positioned in parallel and spaced apart to each other by a fixed distance on the first substrate 12. Each of the third electrodes 22 is positioned on the second substrate 14, and is perpendicular to both the first electrodes 18 and the second electrodes 20. Each of the first electrodes 18 and the second electrodes 20 includes a maintaining electrode 181, 201, and an auxiliary electrode 182, 202, respectively. The maintaining electrodes 181, 201 are made of ITO materials, and the auxiliary electrodes 182, 202 are made of a Cr/Cu/Cr metal alloy. The maintaining electrodes 181, 201 have high resistance and poor conductivity, but are transparent to visible light. The auxiliary electrodes 182, 202 have low resistance to increase the conductivity of its respective electrode 18, 20.
The PDP 10 further includes a dielectric layer 24 covering the surfaces of the first substrate 12, the first electrodes 18, and the second electrodes 20. A protective layer 26 covers the dielectric layer 24. A plurality of barrier ribs 28 are positioned in parallel on the second substrate 14 to define a plurality of discharge spaces 30 of strip shape. Each third electrode 22 is positioned between two adjacent barrier ribs 28. A phosphor layer 32 covers the third electrode 22 and the barrier rib 28 within each discharge space 30 in order to produce red, green, or blue light.
Each of the discharge spaces 30 has a plurality of display units 34. Each display unit is defined by one first electrodes 18, one second electrodes 20, and one third electrodes 22. When an initiating voltage is applied on the first electrode 18 and the third electrode 22, the discharge gas between the first electrode 18 and the third electrode 22 is ionized to form charges on the walls. Both the first electrode 18 and the second electrode 20 are used to drive the plasma formed in these display units 34 for causing a continuous emission of ultraviolet light. Under the ultraviolet light, the phosphor layer 32 emits lights which are transmitted through the transparent first substrate 12 and seen by the user.
The color of lights emitted from the phosphor layer 32 have different colors according to the phosphor materials. Usually, red light is emitted by the phosphor layer 32 when the material of the phosphor layer 32 has ((Y,Gd)BO3), and Eu is added as an activating agent. The green light is emitted when the material of the phosphor layer 32 has Zn2SO4, and Mn is added as an activating agent. Finally, the blue light is emitted when the material of the phosphor layer 32 has BaMgAl14 O23, and Eu is added as an activating agent.
However, the manufacturing method of the phosphor materials is complicated, and the costs of these materials are not cheap. The purity of the red light emitted from the phosphor layer 32 is poor, some remaining images will be produced by the green light, and the blue light will be degraded easily. Further, the phosphor layer 32 coated within the discharge space 30 is easily damaged by plasma bombardment, which shortens the life of the PDP 10.
It is therefore a primary objective of the present invention to provide a full-color PDP that uses different discharge gases to emit variant colors of light. At the same time, a reflecting layer is used to reflect the light emitted by each discharge gas to prevent the light emitting through the rear plate so as to increase the luminescent efficiency of the PDP and avoid the problems associated with the phosphor materials.
In a preferred embodiment, the plasma display panel(PDP) disclosed in the present invention includes a rear plate, a front plate spaced apart and positioned in parallel with the rear plate, and a plurality of barrier ribs positioned in the space between the rear plate and the front plate to define a plurality of discharge space groups. Each discharge space group includes a first discharge space, a second discharge space, and a third discharge space. Each discharge space is filled with the different discharge gases including a first, a second, and a third discharge gas for respectively emitting of one of three primary colors. The rear plate of the PDP has a reflecting layer to reflect the light and prevent the light from penetrating through the rear plate so as to increase the luminescent efficiency of the PDP.
It is an advantage of the present invention that it provides a plasma display panel(PDP) with greater luminescent efficiency. As well, the problems associated with phosphor materials are prevented occurring in the PDP of the present invention. As a result, the life time of the PDP is extended.